Amorphous Carbon Films as Planarization Layers Deposited by Plasma-Enhanced Chemical Vapor Deposition

A dry planarization process utilizing plasma-enhanced chemical vapor deposition (PECVD) of amorphous carbon (a-C:H) films has been developed. The degree of planarization obtained for these films is better than that of many conventional spun-on polymers. Carbon films 2.5 µm thick have been shown to planarize 1.5-µm-deep, 400-µm-wide trenches to within 0.2 µm. The deposition process can be carried out at room temperature with low ion bombardment energy (10 V) and fast deposition rate (300 nm /min). The planarization layers have been used in conjunction with both wet and dry deposited inorganic imaging layers in bilayer resist schemes to form submicrometer patterns.